This invention relates to laminated sheet materials useful in providing decorative and/or functional surfaces to plastic and metal panels for automobiles and the like without the emission of polluting solvents.
Exterior appearance is one of the most critical features in the sale of automobiles. Primary contributors to appearance are shape and finish. The finish on an automobile provides for durability against the exterior environment and the color and appearance attributes of texture, gloss, wet-look, distinctness-of-image, flop and color. Historically, finishes have been applied to automobiles by spray coating a solvent borne resin containing pigments and flakes. The process is highly polluting and costly. The industry has attempted to reduce pollution by replacing the solvent in part with water. While reducing pollutants, pollution is not eliminated and these so called waterborne paints present adhesion problems for certain substrates. More recently, attempts have been made to totally eliminate solvent emissions by the use of xe2x80x9cpaintxe2x80x9d films and film laminates. These film finishes are produced in a controlled process in which any solvents used in manufacture are readily collected for efficient incineration. The xe2x80x9cdryxe2x80x9d films are then formed, molded and bonded to substrates to complete the finishing process in a solvent free process.
The references set out below are germane to the foregoing. U.S. Pat. No. 4,199,489 to Short, issued Apr. 22, 1980. U.S. Pat. No. 4,824,506 to Hoerner et al., issued Apr. 25, 1989. U.S. Pat. 4,769,100 to Short et al., issued Sep. 6, 1988. U.S. Pat. No. 4,818,589 to Johnson et al., issued Apr. 4, 1989. PCT Publication No. WO94/03337 to Duhme et al., published Feb. 17, 1994. U.S. Pat. No. 4,810,540 to Ellison et al., issued Mar. 7, 1989. U.S. Pat. No. 4,931,324 to Ellison et al., issued Jun. 5, 1990. U.S. Pat. No. 4,943,608 to Ellison et al., issued Jun. 24, 1990. U.S. Pat. No. 5,215,826 to Shimanski et al., issued Jun. 1, 1993. U.S. Pat. No. 4,913,760 to Benson et al., issued Apr. 3, 1990. U.S. Pat. No. 5,114,789 to Reafler, issued May 19, 1992. U.S. Pat. No. 5,518,786 to Johnson et al., issued May 21, 1996. European Patent Application 0,285,071 to Spain et al., published Oct. 5, 1988. PCT Publication No. WO96/40480 to Enlow et al., published Dec. 19, 1996. PCT Publication No. WO96/40519 to Enlow et al., published Dec. 19, 1996.
In general, film finishes consist of a clear coat layer, a color layer, an adhesive, a support layer and, optionally, an adhesive layer. While film finishes do eliminate solvents from the assembly plant, they are relatively complicated and expensive to manufacture. One related development in the aforesaid U.S. Pat. No. 5,518,786 reports a Class A film finish suitable for hand application as practiced with hand applied decals and racing stripes. The installed finish consists of:
Constructions similar to this are used to surface molded plastic. In these constructions the clear coat, optionally the tie coat and the base coat are common. The pressure sensitive adhesive is replaced with a structural adhesive, either heat-activated thermoplastic or crosslinking, which is bonded to a support film or sheet.
What is needed is a way to retain the desirable appearance, weathering and environmental attributes of the present film finishes while reducing the cost of manufacture.
In accordance with the present invention, the cost of manufacturing film finishes is reduced by incorporating the base (color) coat into an adhesive, desirably a pressure sensitive adhesive which serves as the bonding medium between the clear coat and the support film or sheet. The resulting construction consists of three [A, B, C] essential xe2x80x9cmajorxe2x80x9d layers. The major layers provide the basic appearance, color, durability and bonding attributes required for a Class A automotive finish. Other finish appearances are possible to meet differing design requirements. xe2x80x9cMinorxe2x80x9d layers [d, e, f, . . . ] may be incorporated to add additional features or enhancements without detracting from the fundamental manufacturing efficiency of the three major layers. The construction profile is:
A/B/C
Each layer will be discussed individually. The optional minor layers may be used individually, in multiple or in total. A preferred construction profile including the potential location of minor layers is:
d/A/e/B/f/C/g
In one embodiment consisting of three major layers, clear coat layer A is a polyvinylidenefluoride (PVDF) polymer or copolymer. The base coat layer B is desirably a permanent type acrylic pressure sensitive adhesive which has been pigmented with pigments and flakes to match the desired color. The support layer C is desirably an extruded film (4 to 10 mils thick) or sheet (11 to 40 mils thick) of a thermoplastic olefin, TPO.
Thus, the present invention relates to a composite decorative sheet consisting of three major layers in which the first, layer A-clear coat, and third, layer C-film, are laminated with an intermediate pigmented pressure-sensitive adhesive, layer B-pigmented adhesive. The composite is characterized as having the appearance and weatherability of a high quality base coat/clear coat paint and said composite having the requisite formability to be shaped into diverse three dimension surfaces.
Other features of the present invention will appear hereinbelow.